Garment ventilation structure

ABSTRACT

A garment such as a sports shirt has concealed ventilation channels; which provide a continuous air channel between permanent openings. In one embodiment, the channels are flexible and non-intrusive and the openings are maintained by springy eyelets The eyelets and channels are attached to the main fabric of the garment providing a robust and a streamlined construction. Another embodiment incorporates active ventilation structures within the channels the structures having a natural vibration frequency matched to a motion frequency spectrum of the wearer. In a further embodiment, the ventilation channels are made of shape memory polymer and change shape in response to changes in temperature.

FIELD OF THE INVENTION

This invention relates to garments including leisure apparel, protectiveapparel, armoured apparel, footwear, sports apparel, and moreparticularly to sports shirts. Although the invention is describedprimarily in terms of shirts, it also has relevance to other kinds ofclothing in which ventilation is important, for example, dresses,trousers and waterproofs.

BACKGROUND OF THE INVENTION

In many activities, where protective sports and leisure apparel is worn,there is a demand for lightweight apparel, which is cool andcomfortable, and has other desirable properties including moisture andperspiration transmission away from the wearer. In addition, fabrics andshirts with good wear characteristics and machine washability aredesirable.

Manufacturers skilled in the art have developed a variety of syntheticfabrics that provide many properties advantageous to their use assports-shirts fabric. COOLMAX® for example, is a polyester fabric, whichhas many of the desirable properties, cited previously. Other fabricsbased on acrylic, acetate, Lycra (registered trade name) and nylon arealso available with similarly desirable properties. U.S. Pat. No.5,297,296 Moretz et al describes a high performance moisture transportfabric.

The technology of sports shirts, including T-shirts, particularly inshape and geometry, follows traditional configuration in the main, withsmall and mainly aesthetic differences between manufacturers. Suchconfigurations rely almost exclusively on the noted high performancefabrics providing the wearer with all the desired characteristics andcomfort.

SUMMARY OF THE INVENTION

Unlike traditional sports shirts, the present invention is directed toimprove wearer comfort by providing novel air channels for ventilationat selected points around the wearer's torso. Other structures may beprovided in conjunction with the ventilation channels. Unlike a shirtthat might provide ventilation by simple open holes or a large mesh, thechannel openings in the present invention are concealed, thus protectingthe wearer from sunlight and harmful U.V. radiation. It may also bedesirable for aesthetic reasons to conceal the holes in the garment.Improved fabrication techniques, which exploit the thermoplastic natureof synthetic fabrics are also employed. It is well known thatthermographic analysis of the human body shows that strenuous activitygenerates localised heat build-up around the chest and back as well asthe upper arm. The thermal profile will naturally vary depending on manyfactors such as body size and the type of activity. Generally, the heartand main upper body muscles are the major areas of heat generation. Suchheat generation induces perspiration in the body, causing the shirtwearer discomfort. Perspiration and discomfort can occur anywhere on thebody if covered by a heavy or insulating layer.

The present invention is intended to improve heat dissipation and reduceperspiration, at selected areas by improved ventilation. The provisionof ventilation by near vertical air columns, guided by the channels,works with the natural direction of heat convection and serves toimprove wearer comfort. For an effective channel depth D, the actualchannel depth, for a channel width w must be D+d where d can calculatedapproximately from the formula d=w²/8 r, where r is the minimumlocalised body radius in a horizontal plane. In one embodiment,ventilation at the front and rear of the torso is provided by fourvertical channels in total. In another embodiment, multiple channels inclose proximity provide ventilation. Embodiments with non-verticalchannels, are also described for application when, for instance, bodyshape or aesthetics impose design constraints. It is not necessary toimprove ventilation at all points within the torso to afford improvementin wearer comfort and coolness. High performance synthetic fabric withknown advantages is used as the main shirt material within theinvention.

In another embodiment of the invention, the ventilation channels areprovided with active ventilation structures within the channels. Thisembodiment is directed to further improve wearer comfort and is againprovided at selected points on the wearer's body. Protective apparel inmany cases encases the body in a heavy or insulating material, thusmaking better ventilation even more desirable. This embodiment continuesto provide ventilation benefits even if covered with another layer,provided the channel openings are unobstructed. This is in contrast to atraditional shirt or garment, which, even if made from high performancemoisture transport fabrics, results in poor cooling as the highperformance fabric benefits are limited if covered by another garmentlayer.

This embodiment provides benefits in rigid material protective garmentsby increased ventilation performance since, unlike prior art,ventilation components are not restricted to being soft, non-intrusivematerials. The active ventilation components are made from a variety ofmaterials and thermoplastics fabrics including polypropylene, polyester,acetate, PVC, ABS, PTFE, Mylar, acrylic, nylon, metal foil or mixturesthereof. Ultra-sonic welding, stitching or adhesive bonding is used tojoin active components to the ventilation channel. Practicaloptimization of such techniques provides flexible active components,robust joints and trim. Wearer comfort is of primary consideration inoverall design geometry, material choice and the forming process. Infabrication, choice of component material, composite layer structure,density, wall thickness and general characteristics is optimised toprovide a functional ventilation structure. In rigid protectivegarments, the choice of material is extended to include metal foils andplastic-metal composites and laminates.

The present embodiment utilizes body motion, whether impulsive orrepetitive movements, to generate resonant vibration in the proposedactive ventilation structures. Fourier analysis of vibrations shows thatany impulse or periodic function can be synthesized as the sum ofsinusoids, each sinusoid being at a different frequency or harmonic. Arepetitive square wave, of frequency 10 Hz, can be approximatelysynthesised by summing sinusoids of frequency 10 Hz, 30 Hz, 50 Hz, 70Hz, 90 Hz etc. Each harmonic has a defined amplitude and phase. In thissynthesis, the amplitude of the first harmonic dominates.

A movement impulse will also contain harmonics, when synthesized. Actualperiodic body movements and impulses may be synthesized reasonablyaccurately with only a few harmonics, because any real impulse ormovement transition edge will not be a sharp step-like function. In thiscase, the fundamental harmonic is even more dominant. Human repetitiveaction may be crudely estimated by considering a fast sports activitysuch as sprint race running where an athlete can travel 100 metres inten seconds approximately. Taking the stride span as 2 metres, we canestimate a repeat period of 0.2 seconds, corresponding to a frequency of10 Hz. If we take account of racket sports activities where fast armmovements occur, in 0.02 seconds approximately, an upper frequency limitcan be estimated as being 50 Hz and certainly lower than 100 Hz. Inactivities where bulky protective clothing is worn, motions may be muchslower. In summary, the frequency spectrum of body motion will containvarious harmonics up to a limit of approximately 50 Hz.

It is also well known that structures such as plates and springs have anatural or resonant frequency of vibration. External periodic forces,even those of small amplitude, acting on a plate or spring can result inhigh amplitude resonant vibrations if their frequency matches thenatural plate frequency. The natural frequency f of a free-endedcantilevered plate of length L is given by f=0.56 K L⁻² where K is thematerial stiffness constant, defined as K=b(Y/12ρ)^(1/2). Y is theelastic modulus, ρ is density and b is the plate thickness. The termcantilever implies that one end of the plate is fixed. Withoutfrictional forces, a resonating plate would vibrate indefinitely atconstant amplitude. In practice, air damping limits the number ofvibration cycles, each cycle exponentially decaying in amplitude. Evenwith small amplitude vibration cycles, plate motion will stir the airwill and assist ventilation. Even if only few vibration cycles occur,ventilation benefits still result; because further vibration stimuluswill continually occur during wearer motion.

In the expression for the natural vibration frequency of a plate, thedimensional and material properties L, b, and Y, ρ respectively, can beselected to give any desired resonant frequency. On the other hand, ingarments and apparel, dimensional choices are limited by otherconsiderations such as the physical width limitations of a ventilationchannel and the fact that any plate should be supported and robust inconstruction. In practice, useful resonant plate length will lie in therange 5 to 50 mm, approximately. Useful resonant plate thickness willlie in the range 0.05 to 1 mm, again approximately. These ranges willalso be influenced by the intended use of the apparel, be it for sportsor purely for protective clothing. In addition, because of the generaldesire for any ventilation component to be as unobtrusive and light aspossible, smaller dimensions are favoured. Again referring to theexpression for natural frequency, it can be seen that limiting thedimensional variables will restrict the choice of material properties toobtain a desired natural frequency. For natural frequencies below 50 Hz,with cm long plates, useful materials will have an elastic moduluswithin the range 500 to 2000 MegaPascals. Polypropylene is one suchmaterial along with nylon, PTFE, and PVC, acrylic, ABS, polyester,Mylar®, acetate, metal foil or mixtures thereof.

Further flexibility in the design choice can be made by optionallyadding localized thickness or mass, at the free end of the plate. Thisresults in a reduction of the natural frequency. Noting again thepractical constraints on component size and weight, any added weightshould not greatly exceed the weight of the plate itself, and willideally be less.

The theoretical expression for natural frequency does not involve theplate width. However, since plate area can affect the damping ofvibrations by, for example, increased air friction, and needs to beconsidered, particularly for large area plates. Also implied in theexpression is that the plate pivot point is fixed. The actual degree offreedom of this point, and its consequent modifications to the naturalfrequency, will depend on the stiffness properties of the material it isattached to and other practical factors. Since forcing perturbationsfrom body motion will have a spectrum of stimulating frequencies, randomand periodic, the absolute value of natural frequency is not ofparamount importance, as long as it falls within the range of theforcing frequencies. Non-planar plate shapes will also affect thepractical natural frequency away from the theoretical value, withoutsignificantly affecting the active ventilation benefits.

The discussions hitherto relating to plates are equally valid forsprings where the equivalent natural frequency fs, is given by fs=(½π)(K/m)^(1/2) where K is the spring stiffness constant and m is the loadmass. For loads around 1 g and a stiffness constant of around 40 N/m, aspring will have natural frequency of around 35 Hz, ignoring dampingeffects. For springs used in series, the effective spring constant K_(e)is given by the well known expression 1/K_(e)=1/K₁+1/K₂ so for aneffective spring constant of 40 N/m two identical springs in series musthave K values of 80 N/m. To maintain a desired natural frequency atgreater loads, the stiffness constant must be increased proportionally.

In yet another embodiment, the ventilation channels possess differentshapes and cross-sectional areas at different temperatures. In this way,comfort would be further improved by providing ventilation at elevatedtemperatures when it is most needed. A first shape would be an openchannel as previously described. A second shape would be a collapsedform of the channel, which may be substantially planar with the shirtfabric. Further shapes would be within the range defined between thefirst and second shapes. In this embodiment, the ventilation channelsare partially made out of at least one shape memory polymer. Optionally,shape memory polymer supports are attached to or integral with theventilation channels. These may take the form of hinged buttresses,eyelets, a liner or some such combination. Optionally, shape memorypolymers are used to control the channel opening geometry, as well asthe channel cross section along the length of the channel.

Shape memory refers to the ability to return from a temporary shape toan original shape, i.e. to the “memorized” shape. Shape memory polymers,or thermally bi-stable polymers as they are also known, are polymersthat possess this particular property. Shape memory polymers operate intwo ways, irreversibly and reversibly. This embodiment mainly exploitsthe former phenomenon, whilst the latter is a volume change resultingfrom a phase change at a certain temperature. Irreversibility refers tothe fact that the polymer shape change is in one direction, from atemporary shape to a permanent shape, in the case of a simple shapememory polymer. The shape memory polymer is chosen such that at leastone and preferably two permanent shapes are memorized, a first shapedominating above a particular temperature and a second shape dominatingbelow the particular temperature. This is possible through the inclusionof at least two different polymer segment species with differenttransition temperatures within the polymer. When taken through aheating-cooling cycle, the polymer will change from the first shape tothe second shape before reverting to the first shape. It follows thatabove the particular temperature, the shape is temporary with respect toone segment, and below the particular temperature the shape is temporarywith respect to the other segment.

The shape memory polymer will undergo a shape change above a particulartemperature and in doing so will alter the geometry of the ventilationchannels, so opening them. For example, as the wearer exerts himself,generated heat will cause the temperature of the shape memory polymer toincrease above the particular temperature, so opening the channels.Ventilation ensues, lowering the wearer's body temperature.Subsequently, the ventilation channels will revert to the collapsedform, thus preventing ventilation. The garment is thus responsive andautomatically adaptive. The shape memory polymers may optionally beactuated by electrical means or other stimuli, such as light orchemicals for example. The collapsed state is more compact andstreamlined, thus reducing the overall garment volume. The garment'svolume only increases when needed, so that at all other times, thereduced volume facilitates storage and renders the channels lessobtrusive to the wearer, or observers. Other configurations of the shapememory polymer are possible, such as composites formed from at least oneshape memory polymer.

For all embodiments, heat forming methods form the panel thermoplasticfabric into flexible air channels. Natural fabrics, including cotton,can readily be coated with a thin thermoplastic layer using verticalcoating techniques and can thus be included as useable fabrics. The endsof each channel are terminated with a springy eyelet, formed by asimilar process. Ultra-sonic welding is used to join the channel panelto the main fabric of the sports shirt. Practical optimization of suchtechniques provides flexible, self-supporting channels, robust jointsand trim.

Wearer comfort is of primary consideration in overall design geometry,material choice and the forming process. A channel structure withnon-intrusive contact against the skin is created by suitable materialselection and channel construction. By non-intrusive we mean that thewearer is not at all discomforted by the channel structure during theactivity and moreover that he or she is virtually unaware of thechannel's presence. At the extreme end of the design mix, a very stiff,unbending and intrusive channel could be provided which would maintain aconstant cross-section channel where airflow is totally unaffected bybody movements. This would of course not be an acceptable solutionbecause of its intrusiveness. At the other end of the design mix, atotally unsupported channel could be provided, but this would have nofunctional value. Practical embodiments that compromise between wearercomfort and channel construction are thus provided, taking account ofthe garment within which the channels are employed.

In fabrication, channel length and eyelet opening positions on the shirtwill be dependent on factors such as the body size and shape, fabricmaterial and the type of sport. Choice of fabric material, its density,gauge thickness and general characteristics will itself be influenced bysimilar factors; accordingly, modifications to the forming and joiningmethod may be needed. Such minor modifications and choices will be wellunderstood by those skilled in the manufacturing art and will not be adeparture from the substance of the invention. The ventilation functionof the channels will ultimately also be affected by demands ofaesthetics which are also part of the manufacturers art. Again, any suchdemands and modifications and will not be a departure from the substanceof the invention.

An object of the present invention is to provide a leisure garment orprotective apparel with improved ventilation and wearer comfort.

It is another object of the invention to provide a garment that providesbeneficial ventilation even if covered with an additional layer or othergarment.

Another object of the present invention is to provide a ventilatedgarment that is robust in construction, hardwearing and washable.

Still another object of the present invention is to provide a ventilatedgarment whose construction is amenable to economic production methods.

It is another object of the invention to provide a sports shirt thatcombines improved ventilation with the skin and the softness of highperformance synthetic fabrics.

These and other objects of the present invention are achieved byproviding self-supporting ventilation channels, non-intrusive to thebody.

BRIEF DESCRIPTION OF THE DRAWING

Embodiments of the invention will now be described by way of examplewith reference to the accompanying drawings in which:

FIG. 1 shows the overall view of a sports shirt with ventilationchannels and eyelets.

FIG. 2 shows a detailed embodiment of the channel cross-section.

FIG. 3 shows another channel cross-section geometry.

FIG. 4 shows details of a channel embodiment with integral liner strip.

FIG. 5 shows an embodiment of a springy eyelet opening and channelassembly.

FIG. 5 a) shows in cut-away view a schematic of the channel and panelfabric arrangement of FIG. 5.

FIG. 5 b) shows in exploded view a schematic of the channel, eyelet andpanel fabric arrangement of FIG. 5.

FIG. 6 shows an embodiment of an integral eyelet opening and linerstrip.

FIG. 7 shows multiple proximate channels.

FIG. 8 shows in isometric view an embodiment of a vertical channel withre-entrant multiple openings.

FIG. 9 shows in isometric view an embodiment of channels with re-entrantmultiple openings, extended horizontally.

FIG. 10 shows in a cut-away perspective view another embodiment of amulti-apertured channel.

FIG. 11 shows part of an apertured garment ventilation channel. FIG. 12shows in front view an array of leaf vanes for active ventilation withina ventilation channel.

FIG. 13 shows the front and plan view of an individual leaf vane.

FIG. 14 shows the front view of a twin leaf vane array with a “U” shapedcentral spine.

FIG. 15 shows a perspective view of a single piece active ventilationvane array attached to springs.

FIG. 16 shows an isometric view of embodiment in which a ventilationchannel is arranged with the shape memory polymer supports.

FIG. 17 shows a cross section of a schematic of a ventilation channel inuse with shape memory polymer supports, in the collapsed and expandedstates.

DETAILED DESCRIPTION OF THE INVENTION

Repeated use of reference numbers in the present specification anddrawings is intended to represent the same or analogous features of theinvention.

It is to be understood that to one skilled in the art that the followingis a description of the exemplary embodiments only and is not intendedas limiting the broader aspects of the present invention, which broaderaspects are embodied in the exemplary fabrication. For illustrative anddescriptive clarity only key items are included in the drawings. Detailsof trim and extraneous flanges for attachment to the apparel itself areshown only where necessary for clarity.

The present invention is directed to sports shirts fabricated withintegral ventilation channels. Referring to FIG. 1, a sports shirt 1, isshown with integral ventilation channels 2, upper opening eyelet 3 andlower opening eyelet 4. For the purposes of descriptive clarity, onlythe front view of the sports shirt is shown and similar channels can beassumed for the rear of the shirt. In practice, the number of channels,their spacing and their eyelet opening starting points will depend onfactors such as the shape of the wearer and the type of sports activity.

The dotted line 5 shows the channel fully extended to the waist band 6.However, the lower opening eyelets 4 are preferentially situated awayfrom the waistband 6, to ensure unobstructed contours for the channelsand openings. Dotted rectangles 7 represent the open areas in the mainfabric of the shirt 8, not in contact with the skin. The upper and loweredges of the rectangles are set back within the channel, thus beingdiscreet and out of view. The channel and opening eyelets are fabricatedas a separate panel 9, and joined to the main fabric 8 by means ofultrasonic welding or stitching. The panel 9 is shown schematically buthas a number of practical arrangements. For instance, the panel can endat the shoulder seam or it can extend to the rear of the shirt, so thatfront and rear ventilation channels are fabricated as one unit. Thepanel material and main body fabric are a synthetic thermoplastic fabricsuch as COOLMAX® polyester.

In FIG. 2, channel 2 has a preferred quasi-rectangular cross-section 10,surface modulated with corrugations 11. The corrugation geometry isshown as a series of arcs but could be any simple geometry such astriangular or rectangular, the important point being that they providerigidity by being formed as a structure with wavy localised planes.

The channel profile is obtained by thermally forming the panel material9. The channel envelope 12, shown dotted, has width of about 15 mm andheight of about 5 mm, with corrugation dimensions around 2 mm in repeatpitch and 1 mm in depth.

Those skilled in the art will recognise that the practical channelprofile and corrugation, shown in the embodiment, may be modifiedaccording to fabric characteristics, however, such modification beingwithin the spirit and substance of the present invention. FIG. 3 isanother channel embodiment, with corrugation applied to the channel wall13. The corrugation structure becomes more necessary for producing aself-supporting channel as the size or span of the profile increases. Asthe span and size of the profile is reduced, the need for corrugationstructure is reduced; however, this being at the expense of reduced airvolume per unit length of channel. Simple, geometric, cross-sectionalprofiles such as triangles, arcs, steps or composites thereof areappropriate for cross-sectional areas typically below 40 mm².

FIG. 4 shows an alternative channel construction useful when the fabricmaterial used is of thin gauge. A thermoplastic liner strip 14 hasthickness of about 0.2 mm and is heat formed integrally with the channelto support it. The liner strip 14, shown in cross-section,preferentially extends against the whole of the channel wall and itslength. When additional non-intrusiveness is required the liner may belimited in extent or length, for instance only supporting the two sidewalls of the channel 10. Alternatively the liner 14 may be perforatedthroughout. Material for the liner strip 14 will have thermal formingproperties that are similar to that of the channel fabric itself.Polyester, PVC, ABS, acetate, acrylic, nylon and composites thereof area few suitable plastics. The liner strip 14 is an additional component,but adds flexibility to the channel profile arrangement and aestheticsand allows choice of thinner, lighter fabrics.

FIG. 5 illustrates the shape of a springy eyelet opening 3 and channel 2in isometric view. For further descriptive clarity, FIG. 5 a) shows anexample of channel 2 and main fabric 8 arrangements. It is obvious thatthe areas shown as main fabric 8 could equally be fabricated as a panel9 as in FIG. 1. Those skilled in the art will be aware of modificationsto these fabrication arrangements, however, such modifications beingwithin the substance of the invention. The eyelet 3 serves severalpurposes:

-   -   a) it protects the end of the fabric channel    -   b) it helps maintain the channel profile    -   c) it transforms the abrupt channel profile into a streamline        shape, i.e. a lower, wider opening having a similar cross        sectional area to the channel, in order to avoid snagging    -   d) it further masks the edge 7 of the channel.

The eyelet is injection moulded from thermoplastic including polyester,PVC, acetate, acrylic, nylon and composites thereof, its thermalcharacteristics matching closely those of the shirt and channel fabric.Mechanically, the eyelet is springy, durable and resistant to tearing. Aslot 15 accepts the leading edge of the channel 2 and is used to anchorthe channel 2 fabric from the underneath, forming a joint afterultra-sonic welding.

Typical welding points 16 are shown. The channel panel and its attachedeyelet terminations 3 can be regarded as an assembly 18. A flange 17 isprovided, which is used to join the panel assembly 18 to the main fabric8, by ultra-sonic welding from the underneath.

A further example of an eyelet and channel assembly is illustrated inFIG. 6. The liner strip 19 has similar function to liner strip 14, as inFIG. 4, supporting the channel cross-sectional shape, but here it isintegral with the springy eyelet 3. Both upper and lower springy eyelets3 and liner 19 are thus a single piece moulding.

FIG. 7 shows the end view of multiple channels. Here multiple, closelyspaced channels 20 are provided. The size of each opening is muchreduced in comparison to channel profile 2, shown dotted. The number ofchannels and their length are variables of choice. The channel profileshown is sinusoidal in nature. Alternative shapes of triangular orrectangular corrugation are also useful practically. The reduced scaleenables the channels to be incorporated as desired without eyeletopenings. It will be obvious to those skilled in the art of shirtfabrication that many traditional means of strengthening the end of thechannels are available, such as reinforcement by stitching, for example.

FIG. 8 shows another embodiment of the invention where the channel 21 isformed as a saw-toothed surface, with an angled wall 22 and a re-entrantopening 23. Re-entrant opening 23 is preferentially open oralternatively capped with a large gauge mesh fabric. The uppermostopening has a springy eyelet 3, joined ultrasonically to the channelpanel 9, to form an assembly. The construction thus provides a channelwith concealed multiple air openings, thereby increasing the ventilationeffects.

The length of the wall 22 may preferentially be about 9 mm and there-entrant opening 23 about 4 mm with a channel width of about 15 mm.The angle between the wall 22 and re-entrant opening 23 ispreferentially about 40 degrees. Those skilled in the art will recognisethat the dimensions of the saw-tooth profile may be varied over a widerange whilst still providing ventilation benefits. The saw tooth 21 willbe heat-formed similar to previous channel embodiments described and, asbefore, with thin gauge fabrics, the saw-tooth profile will be madeself-supporting by means of a liner strip 24.

As before, the choice of liner thermoplastic, its extent and thematerial thickness needed for maintaining the channel profile need to bebalanced against the requirement for a soft, non-intrusive channel.Preferentially, the material will be a thermoplastic matched to theshirt fabric material, such as polyester, PVC, acetate, acrylic, nylonand composites thereof, with average liner wall thickness about 0.2 mm.The liner strip 24 is shaped to duplicate the channel fabric profile.Where additional non-intrusiveness is required, however, the liner isproduced with regular or discrete perforations, to increase theflexibility of the support. The channel saw-tooth profile shown isarranged as in the examples of FIG. 1 and FIG. 2 and their accompanyingdescriptions, where a number of elongated vertical channels areprovided.

Another embodiment as indicated in FIG. 9, has channels 25, elongatedhorizontally. The length of the wall 22 may preferentially be about 9 mmand the re-entrant opening 23 about 4 mm. Depending on material gaugeused, optional vertical struts 26 span all channels and support thesaw-tooth profiles thus maintaining unobstructed openings. The openingscan optionally be capped with a large gauge mesh fabric, the strutthickness and material being similar to that of the liner strip 24.Preferentially, the channel panel 9 extends around the whole body in aband of about 60 mm vertical height. Those skilled in the art willrecognise that the dimensions of the channel profile may be usefullyvaried over a wide range around the preferred embodiment.

FIG. 10 shows a cut-away perspective view of another embodiment wherethe ventilation channel has multi-apertured side walls 10, as well asupper and lower openings terminated with eyelets. Multiple blades 27,are angled upwards to guide air flow, in sympathy with upwards airconvection from the wearer's body. For clarity, the top wall of thechannel is cut-away in the Figure. The blades 27 are inclined at 30degrees to the channel long axis, preferentially with blade-to-aperturelength being in the ratio of about 9:4. Channel width is about 20 mm andblade length is about 5 mm, giving a clear central channel of about 15mm. Blade height is about 4 mm, which, for a channel height of 5 mm,ensures blade edges are not intrusive to the wearer. Preferentially thechannel, flanges and blades are fabricated as an integral injectionmoulding with average wall thickness about 0.2 mm. Preferentially, thematerial will be a thermoplastic similar to the shirt fabric material,such as polyester, PVC, acetate, acrylic, nylon and composites thereof.Because the blades 27 do not serve as supports, their thickness canoptionally be made less than the rest of the moulding. This embodimenthas an additional fabrication advantage in that it can be produced by asimple, single-action mould tool, since in plan view there are nore-entrant surfaces. Those skilled in the art will recognise that avariety of modifications to this embodiment and previous embodiments arepossible, and are within the substance of the invention.

The embodiment shown in FIGS. 11-15 illustrates the active ventilationstructures for use within the ventilation channels. Referring to FIG.11, a vertical “U” shaped ventilation channel 50 has top and bottomopenings 51 and 52 and side wall apertures 53. Static baffles 54 areangled upwards to guide air upwards and to conceal main fabric opening55 from direct view. Only one static baffle pair 54 is shown forclarity. FIG. 12 shows, in front view, a preferred embodiment of anactive ventilation vane array 28, comprising a vertical central spine 29and leaf vanes 30, detailed in front and plan view in FIG. 13. The leafvanes 30 have free-ends 31 and a central aperture 32. An optional load33 at the free-end 31 is integral to the leaf plate 30, the whole platebeing formed by injection moulding, vacuum forming or stamping.Optionally, the load 33 may be a small block of high-density material,which can be bonded to the leaf vane, or encapsulated within it duringits forming process. The weight of this block may be in the rangeW_(p)/10 to 10 W_(p), where W_(p) is the weight of the plate alone. Sucha range allows for practical trimming of the plate natural vibrationfrequency, giving a greater choice of material and plate geometry.

Referring to FIG. 12, the vane array can be beneficially used withinapparel ventilation channels, with the angled part of the leaf vanes 30,approximately in line with the channel aperture openings 53. The centralspine 29 is attached to at least one of the ventilation channel walls.The formed shape of the leaf vane 30 is preferably a monotonic conicfunction, with the full plate areas beyond the aperture 32 havingshallow curvature, and average surface tangent at around 30 degrees tothe vertical. Other shapes are also possible. The central spine 29 has arelatively thick section to provide rigidity, so that vibrations aboutthe plate width are minimal.

Another embodiment, shown in FIG. 14, has two leaf vane arrays supportedby a “U” shaped central spine 29, with openings 34 between each leafvane 30. This arrangement provides the advantages of extra support andease of attachment. In this embodiment, the reduced leaf vane lengthincreases the natural frequency. However, thickness or material choicescan be varied to restore the desired natural frequency.

In FIG. 15, a single piece vane structure 35 is attached to theventilation channel by leaf springs 36. The vane structure isconstructed in one piece, providing ease of production. Angled vanesections 37 are approximately in line with ventilation channel aperture53. Substantially transverse sections 38 have apertures 32, shown aselliptical holes. The longest span of the vane structure is between thetwo leaf springs 36, the span elsewhere being reduced so that vanescannot interfere with the ventilation channel walls.

In practice, the sharp points in the drawing will be considerablyrounded. Although only two leaf springs 36 are shown, those skilled inthe art will recognize that a variety in the number of springs, theirtype and attachment is possible, whilst still being within the scope ofthe invention. The practical choice of effective spring constant enablesthe whole vane structure to have the desired natural vibration frequencyto harness the impulse and periodic motion of the wearer. The wholearrangement in FIG. 15 can optionally be much reduced in scale and madesubstantially planar such that multiple vanes extend over the aperture53. In this case the structure could be beneficially split in two halveswith each planar vane structure close to the external apertures 53, leftand right sides, but not in contact with them. Springs are attached toboth the top and bottom of each planar vane structure.

Where the ventilation channel and surrounding material are rigid, suchas in protective apparel, the active component design choices willenable use of rigid or semi-rigid materials, including metal foilswithin the construction. This is additionally beneficial becauseincreased active ventilation benefits are possible where they are neededmost, since such apparel will normally too be bulky or highlyinsulating. In other leisure and sport apparel, active ventilationbenefits using flexible, non-intrusive components and materials are alsoprovided. The use of all the embodiments described will be ideal forincorporation in rigid surrounding material such as might be used inprotective clothing. In this situation, wall deformations will beminimal and any vane oscillations will be unhindered.

In other apparel, where elastic, soft or semi-rigid thermoplasticfabrics materials are employed, beneficial ventilation is still providedsince it is not essential for the active ventilation to be continuous.It is no doubt obvious that in most activities, however active, that thewearer will be upright most of the time. Any momentary distortions ofthe vane structure or supporting wall, for example as the wearer bends,will soon be followed by restoration of the effective active vanestructure and its beneficial effects as described.

Referring to FIG. 16, an isometric view of a schematic of a ventilationchannel is shown, together with shape memory supports 39. The channel isshown in an intermediate state, between the collapsed and expandedstates, examples of which are shown in FIG. 17. A range of intermediatestates exists between the collapsed and expanded states, and act astransitionary states. The collapsed and expanded states are usually thepermanent states. Corresponding arrangements of the shape memory polymersupports may be programmed into the shape memory polymer's memories. Inthis way, below a particular temperature the polymer is in one state,and above a certain temperature the polymer is in another state. Theparticular and certain temperatures are usually the glass transitiontemperatures of the differing segments within the polymer and are notnecessarily coincident. It will be obvious to the reader skilled in theart that the other mechanical properties of the segments may change withtemperature, thus permitting the polymer supports to change shape.

Thus the expanded state can provide good ventilation, whilst thecollapsed state provides limited or no ventilation, the ventilationchannel being substantially closed. In another embodiment (not shown),there is a shape memory polymer which operates irreversibly, having onlyone permanent state. For example, the expanded state would be thepermanent pre-programmed state. The channel would initially beconfigured in the collapsed state. On application of a suitablestimulus, such as heat, the polymer would expand and the channel wouldexpand, pass through the intermediate states and assume the expandedstate. The channel would then remain in this state until the temperatureis lowered sufficiently that the wearer decides that ventilation is nolonger required, and manually applies force to the channel such that itis reset into its collapsed state. Since the temperature is then belowthe glass transition temperature, the polymer would not revert to theexpanded state.

1. A sports shirt made from a fabric that defines an interior of theshirt and an exterior of the shirt, said sports shirt comprising mainareas of the fabric, said main areas being separated from one another byventilation channels, said channels being self-supporting and flexible,said channels being oriented so as to be substantially vertical whensaid sports shirt is worn by a standing person, each of said channelsdefining an air path along a length of said channel from a lower end ofsaid channel to an upper end of said channel, said channel definingopenings to said exterior of said shirt at said lower end and said upperend of said channel and said channel being open to the interior of saidshirt along at least a major part of the length of said channel.
 2. Asports shirt as defined in claim 1, said channels being located on theshirt such that when said shirt is worn by a standing person contours ofthe substantially vertical channels are substantially unobstructed.
 3. Asports shirt as defined in claim 1 wherein said channels (2) areself-supporting and flexible.
 4. A sports shirt as defined in claim 1,wherein said channels (2) are formed from a thermoplastic fabric andhave a corrugated profile along the channel length, said profile beingdefined by corrugations thermally formed in a said thermoplastic fabric.5. A sports shirt as defined in claim 4, wherein said channelthermoplastic fabric is a fabric material selected from the groupconsisting of polyester, acrylic, PVC, rayon, nylon, acetate andmixtures thereof.
 6. A sports shirt as defined in claim 4, wherein saidchannel thermoplastic fabric is natural fabric material, coated with athermoplastic layer.
 7. A sports shirt as defined in any of claims 4 to6, wherein said channel corrugations have a depth of about 1 mm andrepeat pitch of about 2 mm.
 8. A sports shirt as defined in claim 1,wherein each of said channels is supported by means of a thermoplasticliner.
 9. A sports shirt as defined in claim 1, wherein the across-sectional profile of each channel is about 15 mm wide by about 5mm deep.
 10. A sports shirt as defined in claim 1, in which saidopenings are formed by springy eyelets which terminate the channels saideyelets serving to hold the channels open in a desired cross-sectionalshape and providing protection to edges of said channels where saidchannels are open to the interior of the shirt.
 11. A sports shirt asdefined in claim 10, said eyelets being moulded in a thermoplasticmaterial and attached to the channel and to the main fabric by at leastone attachment method selected from the group comprising heat-forming,adhesive bonding, ultra-sonic welding and stitching, said thermoplasticmaterial being selected from the group comprising polyester, acrylic,PVC, ABS, acetate, nylon, rayon a and mixtures thereof.
 12. A sportsshirt as defined in claim 10 wherein said springy eyelets is areconstructed such that said edges of said channels where said channelsare open to the interior of said shirt are recessed within the eyeletand concealed from direct view from the exterior of the shirt.
 13. Asports shirt as defined in claim 10, wherein said springy eyeletsextends into the channels to support and maintain the desiredcross-sectional shape of said channels.
 14. A sports shirt as defined inclaim 10, wherein each of said springy eyelets has plane flanges forjoining the eyelet to the fabric of said shirt.
 15. A sports shirt asdefined in claim 1, wherein a longitudinal profile of said channels hasa saw-tooth geometry, and wherein said channels define re-entrantopenings.
 16. A sports shirt as defined in claim 15, wherein saidre-entrant openings (23) are capped with a large gauge mesh fabric.17-21. (canceled)
 22. A sports shirt as defined in claim 1, comprisingmultiple apertures in side walls of said channels and internal, angledblades in said channels for guiding ventilation through said apertures.23. A sports shirt as defined claim 1, wherein active leaf vaneventilation structures are provided within the ventilation channels24-41. (canceled)
 42. A sports shirt defined in claim 1, wherein theventilation channels are at least partially made from at least one shapememory polymer.
 43. A sports shirt defined in claim 42, includingchannel supports and/or eyelets and/or channel liners made from said atleast one shape memory polymer and arranged so as to expand and contractthe ventilation channel (2).
 44. A sports shirt as defined in claim 42or claim 43, wherein the ventilation channels are approximately planarwith said main areas of fabric below a particular temperature andprotrude substantially above said main areas of fabric above theparticular temperature.
 45. A sports shirt as defined claim 42, furtherincluding electronic means for actuating the shape memory polymer. 46.(canceled)